Please explain whether the following code is ill-formed:

typedef char T;

void fun(T &p_t) {
p_t.T::~T();
}

Comeau C/C++ 4.3.3 (Aug  6 2003 15:13:37) for ONLINE_EVALUATION_BETA1
Copyright 1988-2003 Comeau Computing.  All rights reserved.
MODE:strict errors C++

In strict mode, with -tused, Compile succeeded

My reasoning goes as follows:
We have to lookup for T in the context of p_t.T by 3.4.3/5 .  We have the
following choices by 3.4.5:
1. p_t is not of class type.  N/A.
2. p_t is not of class type and is not a pointer to a scalar type.  N/A.
3. T is not preceded by ~ and T::~T is qualified.  N/A.
4. If T is a class-name-or-namespace-name.  How can we tell?  We have to
look it up to know what it is.  It is a circular definition.
Assuming we could use some fixpoint logic to resolve this, there is no way
for T to be one.  N/A.
5. T is not preceded by ::.  N/A.
6. T is not followed by <.  N/A.
7. T is not preceded by operator keyword (BTW a link to 12.3.2 is needed
here).  N/A.
I am stuck.




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"Krzysztof    elechowski" wrote:
> Please explain whether the following code is ill-formed:
>
> typedef char T;
>
> void fun(T &p_t) {
> p_t.T::~T();
> }
>
> My reasoning goes as follows:
> We have to lookup for T in the context of p_t.T by 3.4.3/5 .  We have the
> following choices by 3.4.5:
> 1. p_t is not of class type.  N/A.
> 2. p_t is not of class type and is not a pointer to a scalar type.  N/A.
> 3. T is not preceded by ~ and T::~T is qualified.  N/A.
> 4. If T is a class-name-or-namespace-name.  How can we tell?  We have to
> look it up to know what it is.  It is a circular definition.
> Assuming we could use some fixpoint logic to resolve this, there is no way
> for T to be one.  N/A.
> 5. T is not preceded by ::.  N/A.
> 6. T is not followed by <.  N/A.
> 7. T is not preceded by operator keyword (BTW a link to 12.3.2 is needed
> here).  N/A.
> I am stuck.

The intent is that T in this example is looked up by an ordinary
lexical-scope lookup in the context of the complete postfix-expression.
However, you are right that the Standard does not contain a coherent
description of how this case (as well as a number of others with
respect to destructor and pseudo-destructor name lookup) is to be
handled. (See core language issues 244, 305, and 399, in particular.)

I'll open another issue for this case.  Thanks for pointing it out.

-- William M. (Mike) Miller
   Edison Design Group


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